<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <title>Document</title>
  </head>
  <body>
    <!-- 准备好一个容器 -->
    <div id="test"></div>

    <!-- 引入react核心库 -->
    <script type="text/javascript" src="../js/react.development.js"></script>
    <!-- 引入react-dom, 用于支持react操作DOM -->
    <script
      type="text/javascript"
      src="../js/react-dom.development.js"
    ></script>
    <!-- 引入babel, 用于将jsx转为js -->
    <script type="text/javascript" src="../js/babel.min.js"></script>

    <script type="text/babel">
        //创建组件
        //生命周期回调函数 <=> 生命周期钩子函数 <=> 生命周期函数 <=> 生命周期钩子
        class Life extends React.Component{

            state = {
                opacity: 1
            }

            death = ()=>{
                //卸载组件
                ReactDOM.unmountComponentAtNode(document.getElementById('test'));
            }

            //组件挂在完毕
            componentDidMount(){
                this.timer = setInterval(()=>{
                    //获取原状态
                    let {opacity} = this.state;
                    //减小0.1
                    opacity -= 0.1;
                    if(opacity <= 0){
                        opacity = 1;
                    }
                    //设置新的透明度
                    this.setState({opacity});
                },200)
            }

            //组件将要卸载
            componentWillUnmount(){
                clearInterval(this.timer)
            }

            render(){
                console.log("@")
                return (
                    <div>
                        <h1 style={{opacity:this.state.opacity}}>React学不会,怎么办？</h1>
                        <button onClick={this.death}>不活了</button>
                    </div>
                )
            }
        }

        ReactDOM.render(<Life/>,document.getElementById('test'))
    </script>
  </body>
</html>
